July 5-12, 2004

Study updates estimates of air pollution impacts on Torontonians' health

Five common air pollutants contribute to about 1,700 premature deaths and 6,000 hospital admissions in Toronto each year, says a new "burden of illness" study released last week by Dr Barbara Yaffe, Toronto's acting Medical Officer of Health. The study also estimates that exposure to fine particles in Toronto's air contributes to about 12,000 cases of childhood bronchitis and 72,000 days of asthma symptoms each year.

"These premature deaths and hospital admissions are preventable and likely would not have occurred when they did without the exposure to air pollution," said Dr Yaffe.

The estimates cover chronic health effects associated with airborne fine particulates, as well as acute health effects associated with ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide. The report updates previous estimates of the health impact of Toronto's air pollution: in 2000, Toronto Public Health attributed 1,000 premature deaths and 5,500 hospital admissions each year to acute exposure to these pollutants. The new study, unlike its predecessor, includes the impact on death rates of chronic exposure to pollutants as well as the health risk associated with acute exposure; only the latter was addressed by the previous study.

The report also notes that other serious air pollution-linked health conditions affect tens of thousands of people in Toronto each year; these include higher rates of chronic bronchitis, asthma attacks and hospital emergency room visits. The study cites research from around the world demonstrating that air pollution causes these and other impacts, including reduced lung function, lung cancer, high blood pressure and reduced life expectancy.

The Toronto data show that compared with 27 cities over a ten-year period, the city's nitrogen dioxide levels were the fourth highest, surpassed only by Los Angeles, Hong Kong and New York. Pollution trends, says the report, have indicated little improvement in Toronto's air quality over the past two decades. This contrasts with the rest of Ontario, which has shown larger, more consistent reductions in the key pollutants affecting human health.

The study pinpoints the city's transportation sector as the most significant source of air pollution, noting that increases in nitrogen dioxide levels in Toronto have coincided with increased vehicle use and a decline in the use of public transit. Based on data for 2002, the most recent Ministry of Environment data available, Toronto had the highest summertime levels of fine particulates and the highest annual mean levels of nitrogen dioxide, compared to other Ontario communities with air monitoring stations. The transportation sector (including cars, buses and trucks) is Toronto's largest source of nitrogen oxides (including nitrogen dioxide) and accounts for 65% of all emission sources in the city, says the report.

Dr Yaffe also released a report prepared for the Board of Health recommending that the Ontario government be urged to implement a comprehensive action plan to address air pollution in Toronto, addressing the following priorities:

*Reduce emissions from the transportation sector, i.e. by providing sufficient funding to ensure the maintenance and expansion of public transit across the Greater Toronto Area (GTA); curbing urban sprawl and integrating land use and transportation planning across the GTA to decrease dependence on vehicles and encourage alternative, cleaner transportation modes; and eliminating the sale of off-road diesel fuel in large urban centres.

*Reduce emissions associated with fuel and electricity consumption, e.g. by aggressively promoting energy efficiency and renewable energy sources and encouraging cogeneration with high-efficiency natural gas generators, in addition to phasing out coal-fired power plants.

*Reduce emissions from point sources, e.g. by improving the certificate of approval process (for point sources affecting local air quality) and developing a regional air quality plant mandating significant reductions in smog precursor emissions over time (to address point sources contributing to diminished regional air quality).

*Provide support systems for air quality improvements, e.g. developing health-protective air standards to spur action; enhance resources to build air quality capacity within the public health sector; and improving the provincial Air Quality Index and smog messaging system.

More information is available on the Toronto city Web site, www.toronto.ca/health.

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